This is an excerpt from Fundamental Weight Training by David Sandler.
Methods for Creating Training Programs
The decision to start a weight training program is based on an end goal. So training without purpose is like looking for buried treasure without a map—your likelihood of success is slim. Since each person has a unique goal and since adaptation is specific to the stress, there are several methods of constructing a workout program. Each training method has different set, rep, and resistance variations. If you follow the overload principle, you must make sure that the resistance becomes difficult by the last one or two reps of each set. No matter how many reps are required, the resistance should be challenging once you are familiar with the exercise. If you use weights that are too light, it will take longer to see results. If you use weights that are too heavy, you risk burnout, overtraining, and injury.
Training for Muscular Endurance
To gain muscular endurance, you have two choices. You can either extend the set by completing more repetitions or rest for a shorter amount of time between sets. Generally, a set of 12 to 20 reps should last at least 30 seconds but not more than 90 seconds. A prolonged set will encourage lactic acid buildup. This causes that familiar burning sensation and ultimately leads to fatigue. Although lactic acid buildup tends to get a bad rap, if you learn to push through the burn and tolerate the pain, your body will become more accustomed to handling it and further build your muscle's endurance capacity. So the next time you feel the burn, go for a few more reps.
Aim for one to three sets of 15 to 25 repetitions, resting for 30 to 60 seconds between sets. Another alternative is to perform three to five sets of 10 to 15 reps, resting for 15 to 30 seconds between sets.
Training for Muscular Strength
If strength is your goal, you need to use relatively heavy resistance to perform fewer repetitions per set, and you'll need to rest for two to three minutes between sets. The goal of this type of training is to increase the overall strength of a muscle or group of muscles. Strength training usually includes exercises that work the major muscle groups, such as the bench press, seated row, and squat. The catalyst for strength gain, however, is not the number of reps but how hard you work in the lower rep range. If you can easily get 6 to 8 reps and choose to stop, you will not build strength effectively. Neither will you help your strength efforts if the weight is too light and you do more reps. Your last few reps should stop you dead in your tracks and either require a spot to get another rep or force you to stop completely.
For best results, perform one to three sets of 6 to 8 repetitions, resting for two and a half to three minutes between sets.
Training for Muscular Size
Most people who work out want to improve their overall appearance. For men, increasing muscle size is usually the number one goal. Women usually want to become leaner or more toned. Whatever your goal, the results you want take time, and in all cases, size and muscle density are necessary if you wish to have a figure with muscle definition.
Hypertrophy is the technical term for building size, increasing mass, or bodybuilding. Despite popular myth, using very heavy weight as in strength training does not promote size increases as rapidly. Hypertrophy training falls somewhere between strength and endurance training. Training for hypertrophy involves a moderate number of reps with moderate to heavy weight and average rest periods. For those of you afraid to build size rapidly, especially women, don't worry—a few weeks or even months of hypertrophy training will increase muscle size, but getting tree trunk legs and boulder-sized biceps takes many years. Instead, if you are working out to see some definition, to get a few “cuts” in your arms, or to look good at the beach, this is the strategy for you.
The optimal way to increase size is to perform one to three sets of 8 to 12 repetitions (usually 10 to 12), resting for 90 seconds between sets.
Training for Power
Power training is explosive in nature and requires very quick movements using as much weight as possible while still lifting explosively. The advantage of explosive training for sport, although still under investigation, appears to be substantial in athletes playing sports where explosive contact is a regular part of the game. Contact sports such as football have seen some of the best improvements. However, because of the inherent risk, the average person who is looking to get in shape, tone up, and look good probably need not spend time doing explosive lifting. Only skilled lifters and sport-specific athletes should engage in power training.
If you are considering performing explosive movements, use your own body weight, and make sure someone keeps an eye on your form. For true power development, use light to moderate weight for three to five sets of 3 to 5 reps, lifted as explosively as possible.